Take out the eggs and butter. Bring them up to room temperature.
Bake sweet potatoes at 425 degrees for 45 - 50 minutes till fork tender.
Cool and peel the sweet potatoes. Place them into a large mixing bowl.
Pre-bake the pie crusts at 375 degrees for 8-10 minutes. Line the crust with parchment paper and use pie weights or dry beans to hold down the center.
Add butter to the potatoes and whip with an electric mixer until fully blended.
Mix in eggs one at a time.
Blend in sugar
Add cinnamon, nutmeg, and lemon extract.
Sprinkle 1 tbsp. of brown sugar onto the bottom of each piecrust. Spread it evenly.
Pour the mixture into both pie crusts.
Bake 300 degrees for 1 to 1.5 hours or until filling is set and brown.